nano structured materials for hydrogen
TRANSCRIPT
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NANOSTRUCTURED MATERIALS
FOR HYDROGEN
PRODUCTION
PRESENTED BY:J.R.VAISHNAVI
A.ANUSUYA
III B.Tech
(Chemical Engg)
Kongu Engineering College, Erode
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FOREWORD
Energy carrier for the future national research priority
highest energy density of any non-nuclear fuel
can be easily converted to electrical andthermal energy
Fossil fuels like natural gas and crude oil are
obvious sources for the large quantities of
hydrogen needed to initiate the transition to a"Hydrogen Economy".
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BASIC PRINCIPLES OF TANDEM CELL
The Tandem Cell converts the energy of sunlight directlyinto hydrogen gas by splitting water into its constituentelements, Hydrogen and Oxygen.
Consists of two photo-catalytic cells in series
The front cell absorbs the high energy ultraviolet andblue light in sunlight, using nano-crystalline metal oxidethin films to generate electron-hole pairs.
The longer wavelength light in the green to red regionpasses through the front cell and is absorbed in a GraetzelCell producing electrical potential under nearly all lightconditions.
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Connected electrically and together provide thepotential required to split the water molecules in the
electrolyte.
The Cell is fabricated from widely-available and cheapmaterials.
The key to the cell is the performance of the metaloxides in reacting to the photons of the incident light.
The most expensive component of the Cells is currentlythe special glass, on which the nano-crystalline films aredeposited
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BLC approach for catalytic
nanocluster formation
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Flow diagram of the project
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CONSTRUCTION OF TANDEM CELL
This graphic shows schematically our Tandem Cell.
We have a front cell with glass walls containing awater-based electrolyte.
The photocatalytic nanocrystalline film is on therear wall of the cell on conducting glass. The high
energy UV and blue light is absorbed by the film.
Electrons are gathered and carried away andoxygen is formed.
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We use the red and green light which has passedstraight through in a second cell behind to the first.
Dye-solar cell (or Gratzel cell) but it could beformed from photovoltaic cells.
Boosts the energy of the electrons which thencome back to a hydrogen electrode in the front cell.
We would not make cells quite like this graphic, butif we did we would install a transparent membraneto separate hydrogen and oxygen, thus ensuringfuel cell grade hydrogen is produced.
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The Tandem Cell provides:
Hydrogen directly from sunlight and water
Approaching 7.5% efficiency
Renewable energy
No carbon or CO2 emissions
Using state of art technology -photo-catalysis
by nano-crystalline thin films Andmanufactured from low cost materials
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CHARACTERISATION
The adsorption of hydrogen in carbon nanotubeswill be followed using two different techniques:
X-ray spectroscopy and Temperature Desorption
Spectroscopy (TDS). The former will be used to study electronic
structure rearrangements. The latter will measure the strength of
adsorption (i.e. chemisorption, physisorption,and/or van der Waals interaction). The total amount of hydrogen can be calibrated
against hydrogen monolayer coverage on metalsurfaces.
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CONCLUSION Due to their large surface areas with relatively small
mass, SWCNTs have been considered as potentialmaterials for high capacity hydrogen storage.
There is currently much skepticism on carbon nanotubehydrogen storage due to early mistakes in experimentalpublications and therefore a rational basis for highcapacity hydrogen storage materials is being developed
through the systematic nano-materials researchundertaken in this effort.
Thus we can be able to produce and store hydrogen by
using nanomaterials and solar energy using Tandem cell